Service: Store function names as const char* instead of std::string

Uses less memory (strings and function table is stored in constant data)
and speeds up start up (no need to allocate and copy strings).

src/core/hle/service/service.h

@@ -29,7 +29,7 @@ static const int kMaxPortSize = 8; ///< Maximum size of a port name (8 character
 class Manager;
 
 /// Interface to a CTROS service
-class Interface  : public Kernel::Session {
+class Interface : public Kernel::Session {
     // TODO(yuriks): An "Interface" being a Kernel::Object is mostly non-sense. Interface should be
     // just something that encapsulates a session and acts as a helper to implement service
     // processes.
@@ -40,11 +40,11 @@ class Interface  : public Kernel::Session {
      * Creates a function string for logging, complete with the name (or header code, depending 
      * on what's passed in) the port name, and all the cmd_buff arguments.
      */
-    std::string MakeFunctionString(const std::string& name, const std::string& port_name, const u32* cmd_buff) {
+    std::string MakeFunctionString(const char* name, const char* port_name, const u32* cmd_buff) {
         // Number of params == bits 0-5 + bits 6-11
         int num_params = (cmd_buff[0] & 0x3F) + ((cmd_buff[0] >> 6) & 0x3F);
 
-        std::string function_string = Common::StringFromFormat("function '%s': port=%s", name.c_str(), port_name.c_str());
+        std::string function_string = Common::StringFromFormat("function '%s': port=%s", name, port_name);
         for (int i = 1; i <= num_params; ++i) {
             function_string += Common::StringFromFormat(", cmd_buff[%i]=%u", i, cmd_buff[i]);
         }
@@ -59,7 +59,7 @@ public:
     struct FunctionInfo {
         u32         id;
         Function    func;
-        std::string name;
+        const char* name;
     };
 
     /**
@@ -76,13 +76,13 @@ public:
 
         if (itr == m_functions.end() || itr->second.func == nullptr) {
             std::string function_name = (itr == m_functions.end()) ? Common::StringFromFormat("0x%08X", cmd_buff[0]) : itr->second.name;
-            LOG_ERROR(Service, "%s %s", "unknown/unimplemented", MakeFunctionString(function_name, GetPortName(), cmd_buff).c_str());
+            LOG_ERROR(Service, "unknown / unimplemented %s", MakeFunctionString(function_name.c_str(), GetPortName().c_str(), cmd_buff).c_str());
 
             // TODO(bunnei): Hack - ignore error
             cmd_buff[1] = 0;
             return MakeResult<bool>(false);
         } else {
-            LOG_TRACE(Service, "%s", MakeFunctionString(itr->second.name, GetPortName(), cmd_buff).c_str());
+            LOG_TRACE(Service, "%s", MakeFunctionString(itr->second.name, GetPortName().c_str(), cmd_buff).c_str());
         }
 
         itr->second.func(this);